Honeywell RM7895A1014 7800 Series Burner Control Unit

The Honeywell RM7895A1014, also cataloged as the RM7895A1014 Burner Control Unit, operates as a dedicated hardware component for primary flame safeguard execution and automatic burner sequencing within industrial combustion networks. Operating on a 120 VAC (50/60 Hz) power supply, the microprocessor-based relay module processes intermittent pilot ignition, intermittent main flame establishing periods, selectable interlocks, and purge timing dictated by an ST7800A plug-in purge timer card.

Hardware Specifications

4-20 mA HART Loop Protocol and Channel Isolation

The RM7895A1014 utilizes internal signal filtering and channel-to-channel isolation principles to shield sensitive microampere flame sensor amplifier circuits (R7847, R7848, R7849, R7851, R7852, R7861, or R7886) from high-voltage AC ignition interference and line power fluctuations. The solid-state control architecture decouples low-voltage diagnostic loops and purge timing circuits from the main 120 VAC switching relays and external field wiring terminals. This strict isolation topology prevents ground-loop current shifts and eliminates inductive cross-talk, maintaining deterministic sequence control, continuous flame validation, and rapid safety lockout execution.

Frequently Asked Questions

Q: How is the pre-purge timing duration established on the RM7895A1014 relay module?

A: Pre-purge duration is strictly determined by inserting a compatible ST7800A Plug-in Purge Timer Card into the front-facing header interface of the module prior to energizing the unit.

Q: What mandatory hardware components must be combined with the RM7895A1014 for operation?

A: The module requires a Q7800A or Q7800B Universal Wiring Subbase, an ST7800A Plug-in Purge Timer Card, and a compatible 7800 Series Flame Signal Amplifier (such as R7847, R7848, R7849, R7851, R7852, R7861, or R7886).

Field Installation Guidelines

• Mount the designated Q7800A or Q7800B wiring subbase onto a flat, rigid control panel to ensure module rear connector pins mate cleanly without mechanical binding.
• Separate low-voltage flame scanner cabling from 120 VAC control lines and high-voltage ignition transformer leads by running them in isolated, grounded metallic conduits.
• Connect the main equipment grounding conductor directly to the grounding terminal of the Q7800 subbase using a low-impedance copper wire to prevent floating ground loops.
• Torque all subbase wiring screw terminals to standard industrial limits (8 to 10 in-lbs) to ensure vibration-resistant, low-resistance electrical connections across active circuits.